Active safety systems or chassis control systems are designed to improve a motor vehicle's handling, for example at the limits where the driver might lose control of the motor vehicle. The systems compare the driver's intentions, for example, by direction in steering, throttle, and/or braking inputs, to the motor vehicle's response, via lateral acceleration, rotation (yaw) and individual wheel speeds. The systems then control the vehicle, for example, by braking individual front or rear wheels, by steering the wheels, and/or by reducing excess engine power as needed to help correct understeer (plowing) or oversteer (fishtailing).
These systems use several sensors in order to determine the intent of the driver and to determine a driver intended state. Other sensors indicate the actual state of the motor vehicle (motor vehicle response). The systems compare driver intended state with the actual state and decide, when necessary, to adjust the commands for the actuators of the motor vehicle.
In some instances, yaw moment control can adversely affect the wheel slip when a large control action is requested by control systems. This may indirectly result in yaw instability. In order to mitigate the effects, the command should be subjected to tire/road capacity constraints which depend on road conditions, and normal tire forces. It is difficult to achieve an accurate estimation of road conditions. Even with an accurate estimation of road conditions, the existing approaches may fail to manage the interaction of yaw moment and force controllers with wheel slip in transient maneuvers. For example, when a large load transfer happens, the reduced vertical load will decrease the required lateral force capacity for yaw moment control purposes.
Accordingly, it is desirable to provide improved methods and systems for determining control commands for the actuators of the vehicle without an accurate estimation of road conditions. It is further desirable to provide methods and systems for determining the control commands using information from the vehicle corners. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.